The Earth Science Picture of the Day (EPOD) highlights the diverse processes and phenomena which shape our planet and our lives. EPOD will collect and archive photos, imagery, graphics, and artwork with short explanatory captions and links exemplifying features within the Earth system. The community is invited to contribute digital imagery, short captions and relevant links.

Rocks to Roots

As shown above, in Tettegouche State Park on the North Shore of Lake Superior, Minnesota, a family of northern white cedars (Thuja occidentalis) is ganging up on a hapless granite boulder. These hardy trees need an extensive root system to handle the heavy snow loads and occasional strong winds that rake the northwestern Lake Superior area. In addition, they're often trampled by tourists during the summer months. Eventually, they and their progeny will break down the boulders and rocky material, reducing it to consolidated soil more inviting to other types of trees. Weathering by root fungi plays a principal role in this slow but sure process. Frost weathering is also important in regions where freeze-thaw cycles are commonplace.